---10进制设置
---@param sum number @总值
---@param bit number @1~n
---@param val number @1~9
---@return number
return function(sum, bit, val)
    local p = 10 ^ bit
    local a = sum // p * p
    local b = p / 10 * val
    local c = sum % (p // 10)
    return a + b + c
end

